In article Bslaf.1443$5R2.868@trnddc08, (me) wrote:

I had a tentative deal to sell a set of drawings for a Dyke
Delta to anther gentleman.

These drawings were purchased by my father from John Dyke
shortly before my father suddenly died. My father got no
further than the purchase of the drawings, he never had time
to even clean out a space in his shop to begin work.

I now have the drawings and considered them to be something
that I could honestly sell because they had never been used.
They were only taken out of the mailing tube one time.

The prospective buyer was informed by Mr. Dyke that there
would be no builder support because the airplane had not
been started. If there was an unfinished project being
sold, Mr Dyke would help the new buyer finish it. But he
has washed his hands of this set of drawings because when my
father died before he could start, he rendering the drawings
and the rights to build from them void.

From my vantage point this looks like simple greed on the
part of Mr. Dyke for the sale of another set of drawings.

Am I missing something? Has anybody actually seen this
notion applied as a legal precedent in the past?

If this narrative constitutes the totality of the relevant facts of the
situation, this disinterested third party would conclude that Mr. Dyke
is behaving in an entirely legal but reprehensibly small way.

When does human life begin? When does an airplane begin? If your father
took the plans out of the tube, perused them, and spent five minutes
beginning to clear out his shop, I say you have an "unfinished project."